Firestore Numeric Transforms (firebase#91)

samtstern · web-flow · commit 7b3dce5b04e7 · 2019-03-27T10:39:14.000-07:00
diff --git a/build.gradle b/build.gradle
@@ -60,6 +60,7 @@ task("ktlint", type: JavaExec, group: "verification") {
     classpath = configurations.ktlint
     main = "com.github.shyiko.ktlint.Main"
     args = [
+        "--format",
         "--android",
         "--reporter=plain",
         "--reporter=checkstyle,output=${outputFile}",
diff --git a/firestore/app/build.gradle b/firestore/app/build.gradle
@@ -40,7 +40,7 @@ dependencies {
     implementation "com.android.support:multidex:1.0.3"
 
     // Firestore
-    implementation "com.google.firebase:firebase-firestore:18.1.0"
+    implementation "com.google.firebase:firebase-firestore:18.2.0"
 
     // Firebase / Play Services
     implementation "com.google.firebase:firebase-auth:16.2.0"
diff --git a/firestore/app/src/main/java/com/google/example/firestore/DocSnippets.java b/firestore/app/src/main/java/com/google/example/firestore/DocSnippets.java
@@ -454,6 +454,15 @@ public void updateDocumentArray() {
         // [END update_document_array]
     }
 
+    public void updateDocumentIncrement() {
+        // [START update_document_increment]
+        DocumentReference washingtonRef = db.collection("cities").document("DC");
+
+        // Atomically increment the population of the city by 50.
+        washingtonRef.update("population", FieldValue.increment(50));
+        // [END update_document_increment]
+    }
+
     public void updateDocumentNested() {
         // [START update_document_nested]
         // Assume the document contains:
@@ -510,6 +519,9 @@ public void transactions() {
             @Override
             public Void apply(Transaction transaction) throws FirebaseFirestoreException {
                 DocumentSnapshot snapshot = transaction.get(sfDocRef);
+
+                // Note: this could be done without a transaction
+                //       by updating the population using FieldValue.increment()
                 double newPopulation = snapshot.getDouble("population") + 1;
                 transaction.update(sfDocRef, "population", newPopulation);
 
diff --git a/firestore/app/src/main/java/com/google/example/firestore/SolutionCounters.java b/firestore/app/src/main/java/com/google/example/firestore/SolutionCounters.java
@@ -7,6 +7,7 @@
 import com.google.android.gms.tasks.Tasks;
 import com.google.firebase.firestore.DocumentReference;
 import com.google.firebase.firestore.DocumentSnapshot;
+import com.google.firebase.firestore.FieldValue;
 import com.google.firebase.firestore.FirebaseFirestore;
 import com.google.firebase.firestore.FirebaseFirestoreException;
 import com.google.firebase.firestore.QuerySnapshot;
@@ -73,18 +74,9 @@ public Task<Void> then(@NonNull Task<Void> task) throws Exception {
     // [START increment_counter]
     public Task<Void> incrementCounter(final DocumentReference ref, final int numShards) {
         int shardId = (int) Math.floor(Math.random() * numShards);
-        final DocumentReference shardRef = ref.collection("shards").document(String.valueOf(shardId));
-
-        return db.runTransaction(new Transaction.Function<Void>() {
-            @Override
-            public Void apply(Transaction transaction) throws FirebaseFirestoreException {
-                Shard shard = transaction.get(shardRef).toObject(Shard.class);
-                shard.count += 1;
-
-                transaction.set(shardRef, shard);
-                return null;
-            }
-        });
+        DocumentReference shardRef = ref.collection("shards").document(String.valueOf(shardId));
+        
+        return shardRef.update("count", FieldValue.increment(1));
     }
     // [END increment_counter]
 
diff --git a/firestore/app/src/main/java/com/google/example/firestore/kotlin/DocSnippets.kt b/firestore/app/src/main/java/com/google/example/firestore/kotlin/DocSnippets.kt
@@ -335,6 +335,15 @@ abstract class DocSnippets(val db: FirebaseFirestore) {
         // [END update_document_array]
     }
 
+    fun updateDocumentIncrement() {
+        // [START update_document_increment]
+        val washingtonRef = db.collection("cities").document("DC")
+
+        // Atomically incrememnt the population of the city by 50.
+        washingtonRef.update("population", FieldValue.increment(50))
+        // [END update_document_increment]
+    }
+
     private fun updateDocumentNested() {
         // [START update_document_nested]
         // Assume the document contains:
@@ -379,6 +388,9 @@ abstract class DocSnippets(val db: FirebaseFirestore) {
 
         db.runTransaction { transaction ->
             val snapshot = transaction.get(sfDocRef)
+
+            // Note: this could be done without a transaction
+            //       by updating the population using FieldValue.increment()
             val newPopulation = snapshot.getDouble("population")!! + 1
             transaction.update(sfDocRef, "population", newPopulation)
 
diff --git a/firestore/app/src/main/java/com/google/example/firestore/kotlin/SolutionCounters.kt b/firestore/app/src/main/java/com/google/example/firestore/kotlin/SolutionCounters.kt
@@ -3,6 +3,7 @@ package com.google.example.firestore.kotlin
 import com.google.android.gms.tasks.Task
 import com.google.android.gms.tasks.Tasks
 import com.google.firebase.firestore.DocumentReference
+import com.google.firebase.firestore.FieldValue
 import com.google.firebase.firestore.FirebaseFirestore
 
 /**
@@ -48,13 +49,7 @@ class SolutionCounters(val db: FirebaseFirestore) {
         val shardId = Math.floor(Math.random() * numShards).toInt()
         val shardRef = ref.collection("shards").document(shardId.toString())
 
-        return db.runTransaction { transaction ->
-            val shard = transaction.get(shardRef).toObject(Shard::class.java)
-            shard!!.count += 1
-
-            transaction.set(shardRef, shard!!)
-            null
-        }
+        return shardRef.update("count", FieldValue.increment(1))
     }
     // [END increment_counter]
 
